/cgl/ - Cosplay & EGL

What material would be best suited for making a prop sword blade with a fairly low thickness (<1/2 in)?

I'm looking at something like balsa or luan board since I don't know if I can get thin enough sheets of insulation foam or if it would resist cracking as much as sealed wood.

Pic related is the sword, the blade will likely be around 3-3.5 feet long and slot into the ornate bit above the crossguard for stability, since it'll be too thin to run a pine dowel through.